The present invention relates to liquid crystal display apparatus, and in particular to liquid crystal display apparatus wherein a flexible printed circuit board with a pattern formed on one surface is bent approximately at the center in two thus configuring a first pattern surface and a second pattern surface at the rear of the first pattern surface.
Portable terminal apparatus such as a portable telephone set and a PHS (Personal Handyphone System) terminal is getting more compact and lightweight year by year. Recently, a low-profile design and a large liquid crystal display have been key points for marketability of a product.
A plastic casing of liquid crystal display apparatus instead of a conventional glass casing has been contributed to a lightweight and low-profile design.
The plastic liquid crystal display apparatus, however, cannot accept the thermal crimping method at joints; thus the liquid crystal display apparatus cannot use flexible printed circuit boards (flexible boards) via the TAB (Tape Attach Bonding) method employed for a conventional glass liquid crystal display apparatus.
As the number of displayed characters increases, the number of joints with the main printed circuit board increases. This allows jointing via the thermal crimping method by using a COF (Chip On Film) flexible printed circuit board and reduces the number of joint poles with the main printed circuit board.
FIG. 4 is a side sectional view of conventional liquid crystal display apparatus assembled to configure a unit.
Referring to FIG. 4, liquid crystal display apparatus having a flexible board (for example a COF flexible board) 31 is assembled so as to be wrapped by a holding member 32 to form a unit. In the unit, contacts 33 provided on the flexible board 31 come in contact with connectors 35 provided on a printed circuit board 34.
FIG. 5 is a perspective plan view of conventional liquid crystal display apparatus. The liquid crystal display (LCD) portion is arranged below the apparatus shown in FIG. 5. Referring to FIG. 5, the liquid crystal display apparatus is composed of a liquid crystal display device (LCD) 37 and a flexible board 31 such as a COF flexible board. The flexible board 31 such as a COF flexible board is provided with positioning holes 39 and mounts contacts 33 to make contact with connectors on the printed circuit board and associated parts 40 related to liquid crystal display operation.
FIG. 6 is a side sectional view of another conventional liquid crystal display apparatus assembled to configure a unit.
Referring to FIG. 6, liquid crystal display apparatus having a TAB 41 is assembled so as to be wrapped by a holding member to form a unit. In the unit, associated parts provided on the TAB 41 are attached to the TAB 41 via bonding.
Referring to FIG. 7, bosses 42 provided on the holding member 32 are adapted to be in the positioning holes in the flexible board 31 such as a COF board as well as to pass through the positioning holes in the printed circuit board 34, and fixed to the printed circuit board 34 via a hook 43 provided on the holding member 32.
As shown in FIG. 5, in case the contact method is used for jointing with the main printed circuit board, there is a problem that the chip-mounted surface of the flexible printed circuit board mates oppositely with the contacts on the main printed circuit board, from the viewpoint of the design of the main unit.
The COF flexible printed circuit board uses a single-sided pattern. Thus there is a problem that the chip-mounted surface of the flexible printed circuit board mates oppositely with the contacts on the main printed circuit board.
The invention solves the aforementioned conventional problem and aims at providing liquid crystal display apparatus that can be configured using a flexible printed circuit board (flexible board) having a single-sided pattern and adapted to facilitate provide assembly of the apparatus.
The first aspect of the invention is liquid crystal display apparatus comprising a liquid crystal display device and a flexible board with a pattern formed on one surface, wherein the flexible board is bent approximately at the center in two and that the inner surfaces are hermetically fixed thus configuring a first pattern surface and a second pattern surface at the rear of the first pattern surface.
Via this configuration, the liquid crystal display apparatus can be configured using a flexible board having a single-sided pattern and assembly of the apparatus can be facilitated.
The second aspect of the invention is liquid crystal display apparatus having a flexible board connected to a liquid crystal display panel, wherein electronic parts are mounted adjacently to the liquid crystal display panel and contacts are provided adjacently to the electronic parts on one surface of the flexible board and that the flexible board is bent in S-shape and the liquid crystal display panel, electronic parts and contacts are stacked from top to bottom, in order to attach the flexible board to a printed circuit board, with the liquid crystal display surface exposed on the top, electrical parts sandwiched and contacts exposed on the bottom, thereby electrically connecting the contacts on the flexible board to the contacts provided on the printed circuit board.
Via this configuration, a liquid crystal display panel to which a flexible board with electrical parts and contacts provided on one surface can be attached to a printed circuit board.
The third aspect of the invention is liquid crystal display apparatus comprising a liquid crystal display panel, a flexible board to be connected to the liquid crystal display panel, and holding means for holding the liquid crystal display panel and the flexible board, wherein electronic parts are mounted adjacently to the liquid crystal display panel and contacts are provided adjacently to the electronic parts on one surface of the flexible board in advance, wherein the flexible board is connected to the liquid crystal display panel, and wherein the flexible board is bent in S-shape and attached to the holding means, with the liquid crystal display panel, electronic parts and contacts stacked from top to bottom, thereby configuring a liquid crystal display panel unit.
Via this configuration, it is possible to assemble a liquid crystal display panel unit, with the liquid crystal display surface exposed on the top, electrical parts sandwiched and contacts exposed on the bottom.
The fourth aspect of the invention is liquid crystal display apparatus having a flexible board which is electrically connected to a liquid crystal display device and attached to a holding member, and contacts provided on the flexible board and connectors provided on a printed circuit board being electrically connected, wherein the flexible board is provided with a bending section whereby the flexible board can be bent approximately at the center in two, wherein the flexible board is provided with the positioning holes symmetrical with respect to a line about the bending section, wherein contacts electrically connected to the printed circuit board are provided near the positioning hole at the frond end of the flexible board, that associated parts for driving the liquid crystal display device are mounted near the positioning hole at the end behind the bending section of the flexible board, and wherein the associated parts are positioned on and attached to the holding member after the bending section is bent, thereby allowing electrical connection with the printed circuit board.
Via this configuration, the liquid crystal display apparatus can be configured using a flexible board having a single-sided pattern and assembly of the apparatus can be facilitated.
The fifth aspect of the invention is liquid crystal display apparatus according to the fourth aspect of the invention, further comprising a reinforcing plate is bonded to the rear side of the flexible board comprising the positioning hole at the front end of the flexible board and the contacts electrically connected to the printed circuit board.
Via this configuration, the contacts provided on the flexible board can come in contact with connectors mounted on the printed circuit board.
The sixth aspect of the invention is liquid crystal display apparatus according to the fourth aspect of the invention, wherein the bending section provided on the flexible board is equipped with notches in approximate half rectangles on both sides of the flexible board and a notch in an approximate rectangle in the center, respectively.
Via this configuration, the bending section can be bent with ease.
The seventh aspect of the invention is liquid crystal display apparatus according to the fourth aspect of the invention, wherein the contacts electrically connected to the printed circuit board are provided outside the positioning hole at the front end of the flexible board and that associated parts for driving the liquid crystal display device are provided inside the positioning hole at the end behind the bending section of the flexible board.
Via this configuration, noises coming from signal sources do not overlap with each other even when the flexible board is bent.
The eighth aspect of the invention is liquid crystal display apparatus according to the seventh aspect of the invention, wherein the associated parts for driving the liquid crystal display device provided inside the positioning hole at the end behind the bending section of the flexible board are mounted so as to keep their weight balanced about the center of the flexible board.
Via this configuration, it is possible to arrange parts mounted on a flexible board in a balanced way thereby smoothing out the load on the flexible board.